The present disclosure relates to the recovery of a light noble gas from a gas mixture containing the light noble gas and at least one other component. The light noble gas may be helium, neon, or argon.
A variety of processes and techniques have been developed to separate and recover light noble gases from multicomponent gas streams. Such processes include stand-alone membrane separation units, stand-alone cryogenic units, and combinations of membrane separation units, cryogenic units, and pressure swing adsorption (PSA) units. As used herein, the term “pressure swing adsorption” includes “vacuum swing adsorption” and “vacuum pressure swing adsorption.”
Disclosures related to such processes and/or techniques include WO2016/096104; DE102007022963; and U.S. Pat. Nos. 3,250,080; 3,324,626; 4,077,779; 4,690,695; 4,701,187; 4,717,407; 4,783,203; 5,542,966; 8,152,898; 8,268,047; and US 2017/0312682.
It is desirable in the industry to recover light noble gases from various feed streams that contain the desired light noble gas.
For example, it is desirable to recover helium from a feed stream (e.g. natural gas) having a low helium concentration, e.g. from 0.1 mole % to 4 mole % or from 0.1 mole % to 2 mole % helium, or from 0.1 mole % to 1 mole % helium. Other example feed streams include nitrogen rejection unit (NRU) vent streams, CO2 liquefaction vent streams, recycle streams in manufacturing processes, recovery streams in airship filling processes, reboiler non-condensable vents in air separation units, high pressure gaseous nitrogen (HPGAN) from air separation units, reflux to low pressure columns in air separation units, or liquefied nitrogen storage tank vents.
It is desirable in the industry to recover light noble gases from a feed streams where the concentration of the light noble gas varies over time.
It is also desirable in the industry to produce a product gas containing a light noble gas within target concentration specifications for feed streams where the concentration of the light noble gas varies.